公开(公告)号：US20240012167A1

公开(公告)日：2024-01-11

申请号：US18329133

申请日：2023-06-05

Applicant: EXFO Inc.

Inventor： Hongxin CHEN ,  Michel LEBLANC ,  Michel LECLERC

IPC: G01V1/22 ,  G01V1/00

CPC classification number: G01V1/226 ,  G01V1/001

Abstract: There is provided a method and an apparatus of fiber optic distributed acoustic sensing (DAS) which can use low-cost coherent laser as well as low-cost acquisition and processing electronics and which can still provide reliable monitoring results for optical fiber monitoring and troubleshooting applications in optical fiber telecommunication networks. Such low-cost solution is made possible by employing grouped data signal processing. Data is processed over independent groups of data to provide an independent DAS signal for each group. This allows measurements to be less sensitive to laser fluctuations and thereby reduces coherent laser technical specification requirements and allows the use of a low-cost coherent laser (thereby reducing the cost of the laser) as well as low-cost acquisition and processing electronics.

公开(公告)号：US20240344878A1

公开(公告)日：2024-10-17

申请号：US18624663

申请日：2024-04-02

Applicant: EXFO Inc.

Inventor： Hongxin CHEN ,  Michel LEBLANC

IPC: G01H9/00 ,  G01D5/353

CPC classification number: G01H9/004 ,  G01D5/35358

Abstract: There is provided a method and system of frequency dithered distributed acoustic sensing (FD-DAS) using group data signal processing, where the continuous wave (CW) coherent laser's optical frequency or optical phase for the FD-DAS interrogator may be set in evenly or randomly distributed manner for different data groups but they are kept as constant or with negligibly variation within each data group. Such FD-DAS may be used to improve acoustic or vibration signal measurement reliability, to allow to use a low-cost single-frequency laser such as a DFB laser, and/or to suppress polarization fading effect.